Spondylosis deformans is a degenerative, noninflammatory condition of the spinal column characterized by the production of bone spurs or osteophytes along the edges of the bones of the spine. A bony spur may develop in a single spot on the spine; more commonly, there will be multiple bone spurs in several different locations along the spine. The most common places that spondylosis deformans lesions develop are along the thoracic vertebrae (chest), especially at the junction between the rib cage and the abdomen, in the lumbar spine (lower back) and in the lumbosacral spine (around the hips and back legs). In some cases the bony spurs may become large enough that they appear to form a complete bridge between adjacent vertebral bones. (show rads of spondylosis)
Any dog, and even cats, can get spondylosis deformans. However, older, large-breed dogs are at highest risk for developing spondylosis deformans. In most dogs, this degenerative condition will begin to develop by 10 years of age, and some researchers feel that every dog will develop this condition if it lives long enough.
Most dogs with spondylosis deformans show no symptoms. Occasionally, the bone spurs restrict the movement of the spine and the dog may appear to be stiffer and less flexible. A decrease in muscle mass over the affected area may also be noticed. If a bone spur grows near a nerve root as it comes out of the spinal canal, it may put pressure on the nerve, causing pain or lameness. If the condition is painful, the dog may whine or cry when touched along affected areas of the back. It is also possible for one of the osteophytes to break off, which can also lead to pain.
Spondylosis deformans is diagnosed using radiographs. In some cases, it may also be diagnosed with CT scans or MRIs, but that is usually when the presence of a more serious condition is suspected. Often, spondylosis is found incidentally on radiographs that are actually being taken for some other reason.
Spondylosis deformans is a chronic condition that is associated with aging, and it often develops as a secondary problem related to degenerative disease of the intervertebral discs. In the normal spine, the vertebral bones are joined by ligaments allow the spine to be flexible while protecting the spinal cord. There is an intervertebral disc between each vertebral bone, and these discs act as shock absorbers and cushions. If the intervertebral discs become damaged, the joints of the spine become less stable. The bone spurs that occur in spondylosis deformans develop to re-establish the stability of the weakened joints. The formation and growth of the osteophytes is triggered by instability and they grow as large as is necessary to reinforce the diseased joint.
Many dogs with spondylosis are non-painful. However, in patients that are experiencing pain and discomfort, NSAIDs, exercise restriction, and physical therapy can prove beneficial. Weight management is also important in relieving some of the stress on the joints and decreasing some of the instability. In the uncommon circumstance that the osteophytes are causing compression of the spinal cord, they may have to be removed surgically.
Spondylosis deformans is a relatively normal finding in dogs as they age, and may have a genetic component. Therefore, there are currently no known measures that can be taken to prevent spondylosis.
Generally the prognosis for a dog diagnosed with spondylosis deformans is very good, since the majority of cases show no clinical signs or pain. In dogs that do show discomfort, it can usually be managed with anti-inflammatories and pain relievers, as well as physical therapy. Keep in mind that dogs can develop spondylosis that compresses a nerve, in which case more obvious symptoms such as lameness may be noted. Therefore, if your dog is diagnosed with spondylosis, regular physical exams are important for monitoring the progression of the disease.